org.apache.hadoop.hbase.rsgroup

Class RSGroupBasedLoadBalancer

java.lang.Object

org.apache.hadoop.hbase.rsgroup.RSGroupBasedLoadBalancer

All Implemented Interfaces:

ConfigurationObserver, LoadBalancer, RSGroupableBalancer, Stoppable

@InterfaceAudience.Private
public class RSGroupBasedLoadBalancer
extends Object
implements RSGroupableBalancer, LoadBalancer

GroupBasedLoadBalancer, used when Region Server Grouping is configured (HBase-6721) It does region balance based on a table's group membership. Most assignment methods contain two exclusive code paths: Online - when the group table is online and Offline - when it is unavailable. During Offline, assignments are assigned based on cached information in zookeeper. If unavailable (ie bootstrap) then regions are assigned randomly. Once the GROUP table has been assigned, the balancer switches to Online and will then start providing appropriate assignments for user tables.

Field Summary

Fields

Modifier and Type	Field and Description
static String	HBASE_GROUP_LOADBALANCER_CLASS Config for pluggable load balancers

Fields inherited from interface org.apache.hadoop.hbase.master.LoadBalancer

BOGUS_SERVER_NAME

Constructor Summary

Constructors

Constructor and Description
RSGroupBasedLoadBalancer()
RSGroupBasedLoadBalancer(RSGroupInfoManager RSGroupInfoManager)

Method Summary

Modifier and Type	Method and Description
List<RegionPlan>	balanceCluster(Map<ServerName,List<HRegionInfo>> clusterState) Perform the major balance operation
List<RegionPlan>	balanceCluster(TableName tableName, Map<ServerName,List<HRegionInfo>> clusterState) Perform the major balance operation
Configuration	getConf()
Map<HRegionInfo,ServerName>	immediateAssignment(List<HRegionInfo> regions, List<ServerName> servers) Sync assign a region
void	initialize() Initialize the load balancer.
boolean	isOnline()
boolean	isStopped()
void	onConfigurationChange(Configuration conf) This method would be called by the ConfigurationManager object when the Configuration object is reloaded from disk.
ServerName	randomAssignment(HRegionInfo region, List<ServerName> servers) Get a random region server from the list
void	regionOffline(HRegionInfo regionInfo) Marks the region as offline at balancer.
void	regionOnline(HRegionInfo regionInfo, ServerName sn) Marks the region as online at balancer.
Map<ServerName,List<HRegionInfo>>	retainAssignment(Map<HRegionInfo,ServerName> regions, List<ServerName> servers) Assign regions to the previously hosting region server
Map<ServerName,List<HRegionInfo>>	roundRobinAssignment(List<HRegionInfo> regions, List<ServerName> servers) Perform a Round Robin assignment of regions.
void	setClusterStatus(ClusterStatus st) Set the current cluster status.
void	setConf(Configuration conf)
void	setMasterServices(MasterServices masterServices) Set the master service.
void	stop(String why) Stop this service.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

HBASE_GROUP_LOADBALANCER_CLASS

public static final String HBASE_GROUP_LOADBALANCER_CLASS

Config for pluggable load balancers

See Also:

Constant Field Values

Constructor Detail

RSGroupBasedLoadBalancer

@InterfaceAudience.Private
public RSGroupBasedLoadBalancer()

RSGroupBasedLoadBalancer

@InterfaceAudience.Private
public RSGroupBasedLoadBalancer(RSGroupInfoManager RSGroupInfoManager)

Method Detail

getConf

public Configuration getConf()

setConf

public void setConf(Configuration conf)

setClusterStatus

public void setClusterStatus(ClusterStatus st)

Description copied from interface: LoadBalancer

Set the current cluster status. This allows a LoadBalancer to map host name to a server

Specified by:

setClusterStatus in interface LoadBalancer

setMasterServices

public void setMasterServices(MasterServices masterServices)

Description copied from interface: LoadBalancer

Set the master service.

Specified by:

setMasterServices in interface LoadBalancer

balanceCluster

public List<RegionPlan> balanceCluster(TableName tableName,
                                       Map<ServerName,List<HRegionInfo>> clusterState)
                                throws HBaseIOException

Description copied from interface: LoadBalancer

Perform the major balance operation

Specified by:

balanceCluster in interface LoadBalancer

Returns:

List of plans

Throws:

HBaseIOException

balanceCluster

public List<RegionPlan> balanceCluster(Map<ServerName,List<HRegionInfo>> clusterState)
                                throws HBaseIOException

Description copied from interface: LoadBalancer

Perform the major balance operation

Specified by:

balanceCluster in interface LoadBalancer

Returns:

List of plans

Throws:

HBaseIOException

roundRobinAssignment

public Map<ServerName,List<HRegionInfo>> roundRobinAssignment(List<HRegionInfo> regions,
                                                              List<ServerName> servers)
                                                       throws HBaseIOException

Description copied from interface: LoadBalancer

Perform a Round Robin assignment of regions.

Specified by:

roundRobinAssignment in interface LoadBalancer

Returns:

Map of servername to regioninfos

Throws:

HBaseIOException

retainAssignment

public Map<ServerName,List<HRegionInfo>> retainAssignment(Map<HRegionInfo,ServerName> regions,
                                                          List<ServerName> servers)
                                                   throws HBaseIOException

Description copied from interface: LoadBalancer

Assign regions to the previously hosting region server

Specified by:

retainAssignment in interface LoadBalancer

Returns:

List of plans

Throws:

HBaseIOException

randomAssignment

public ServerName randomAssignment(HRegionInfo region,
                                   List<ServerName> servers)
                            throws HBaseIOException

Description copied from interface: LoadBalancer

Get a random region server from the list

Specified by:

randomAssignment in interface LoadBalancer

Parameters:

region - Region for which this selection is being done.

Returns:

Servername

Throws:

HBaseIOException

immediateAssignment

public Map<HRegionInfo,ServerName> immediateAssignment(List<HRegionInfo> regions,
                                                       List<ServerName> servers)
                                                throws HBaseIOException

Description copied from interface: LoadBalancer

Sync assign a region

Specified by:

immediateAssignment in interface LoadBalancer

Returns:

Map regioninfos to servernames

Throws:

HBaseIOException

initialize

public void initialize()
                throws HBaseIOException

Description copied from interface: LoadBalancer

Initialize the load balancer. Must be called after setters.

Specified by:

initialize in interface LoadBalancer

Throws:

HBaseIOException

isOnline

public boolean isOnline()

regionOnline

public void regionOnline(HRegionInfo regionInfo,
                         ServerName sn)

Description copied from interface: LoadBalancer

Marks the region as online at balancer.

Specified by:

regionOnline in interface LoadBalancer

regionOffline

public void regionOffline(HRegionInfo regionInfo)

Description copied from interface: LoadBalancer

Marks the region as offline at balancer.

Specified by:

regionOffline in interface LoadBalancer

onConfigurationChange

public void onConfigurationChange(Configuration conf)

Description copied from interface: ConfigurationObserver

This method would be called by the ConfigurationManager object when the Configuration object is reloaded from disk.

Specified by:

onConfigurationChange in interface ConfigurationObserver

Specified by:

onConfigurationChange in interface LoadBalancer

stop

public void stop(String why)

Description copied from interface: Stoppable

Stop this service.

Specified by:

stop in interface Stoppable

Parameters:

why - Why we're stopping.

isStopped

public boolean isStopped()

Specified by:

isStopped in interface Stoppable

Returns:

True if Stoppable.stop(String) has been closed.